Metabolomic analysis to understand the mechanism of Ti3C2Tx (MXene) toxicity in Daphnia magna.

Due to their potential release into the environment, the ecotoxicity of Ti3C2Tx (MXene) nanomaterials is a growing concern. Unfortunately, little is known about the toxic effects and mechanisms through which Ti3C2Tx induces toxicity in aquatic organisms. The aim of this study is thus to investigate the toxic effects and mechanisms of Daphnia magna upon exposure to Ti3C2Tx with different sheet sizes (100 nm [Ti3C2Tx-100] and 500 nm [Ti3C2Tx-500]) by employing conventional toxicology and metabolomics analysis. The results showed that exposure to both Ti3C2Tx-100 and Ti3C2Tx-500 at 10 µg/mL resulted in a significant accumulation of Ti3C2Tx in D. magna, but no effects on the mortality or growth of D. magna were observed. However, the metabolomics results revealed that Ti3C2Tx-100 and Ti3C2Tx-500 induced significant changes in up to 265 and 191 differential metabolites in D. magna, respectively, of which 116 metabolites were common for both. Ti3C2Tx-100-induced metabolites were mainly enriched in phospholipid, pyrimidine, tryptophan, and arginine metabolism, whereas Ti3C2Tx-500-induced metabolites were mainly enriched in the glycerol-ester, tryptophan, and glyoxylate metabolism and the pentose phosphate pathway. These results indicated that the toxicity of Ti3C2Tx to D. magna has a size-dependent effect at the metabolic level, and both sheet sizes of Ti3C2Tx can lead to metabolic disturbances in D. magna by interfering with lipid and amino acid metabolism pathways.

Amino-carboxyl cellulose for adsorption of Cd2+ and Pb2.

An amino-carboxyl cellulose was synthesized using the grafting of glycine on the aldehyde cellulose through a Schiff base reaction for the adsorption of heavy metals with Cd2+ and Pb2+ as the representative. Higher affinity of the amino-carboxyl cellulose was found at pH 4.5-5.0 for Cd2+ and 4.0-5.5 for Pb2+. The equilibrium was achieved within 30 min. The adsorption capacities of amino-carboxyl cellulose (Cd2+: 85.7 mg g-1, Pb2+: 115.1 mg g-1, Cu2+: 68.2 mg g-1, Co2+: 60.1 mg g-1, Ni2+ 48.5 mg g-1 and Zn2+: 52.8 mg g-1) at 30 °C were observed. A mild increase in the adsorption capacities of Cd2+ and Pb2+ from 15 to 45 °C was observed. Adsorption data correlated well with the Langmuir and pseudo-second order equations, illustrating chemisorption of Cd2+ and Pb2+ by the amino-carboxyl cellulose. The adsorption of the amino-carboxyl cellulose for Cd2+ and Pb2+ was a spontaneous and endothermic. The amino-carboxyl cellulose owned a high reusability after 4 cycles.

Biomass-derived nanostructured carbons and their composites as anode materials for lithium ion batteries.

Since ever-increasing energy demands stimulated intensive research activities on lithium-ion batteries (LIBs), biomass as an earth-abundant renewable energy source has played an intriguing and promising role in developing sustainable biomass-derived carbons and their composite materials for high-performance LIB anodes. Different from other materials (e.g., silicon, tin, metal oxides, etc.), biomass-derived carbons and their composite materials have been applied more and more to LIBs due to their advantages such as low cost, green and eco-friendly synthesis, easy accessibility, sustainable strategy, and improved battery performance, including capacity, cycling property, and stability/durability. This tutorial review focusing on biomass-derived carbons and their composites in the application of LIB anodes will act as a strategic guide to build a close connection between renewable materials and electrochemical energy storage devices. Also, this review provides a critical analysis and comparison of biomass-derived carbons and their composites for LIB anodes, coupled with an important insight into the remaining challenges and future directions in the field.